Dendrimers and magnetic resonance imaging

The multivalent character of dendrimers has positioned these well-defined, highly branched macromolecules at the forefront in the development of new contrast agents for biomedical magnetic resonance imaging (MRI). By modifying the periphery of the dendrimer with gadolinium(III) chelates, the relaxivity of the resulting MRI contrast agent is increased considerably, compared to low molecular weight Gd(III) chelates. The monodisperse character of dendrimers creates a unique opportunity to introduce dendritic MRI contrast agents into clinics. In addition, a prolonged vascular retention time is obtained due to the larger size of the dendritic molecules. By using dendrimers as multivalent scaffolds carrying multiple ligands, the interaction between ligand and marker can be enhanced through multivalent interactions. Current research focuses on the combination of multivalent targeting and enhanced relaxivity. This paper describes the application of dendrimers in biomedical MRI.